U.S. patent number 5,090,774 [Application Number 07/586,449] was granted by the patent office on 1992-02-25 for acoustically decoupled underbody for a motor vehicle.
This patent grant is currently assigned to Volkswagen AG. Invention is credited to Franz Dolla.
United States Patent |
5,090,774 |
Dolla |
February 25, 1992 |
Acoustically decoupled underbody for a motor vehicle
Abstract
An underbody for a motor vehicle has side rails with inclined
portions and parallel sills and a floor panel joined by a
transverse support arrangement which is spaced apart from the side
rails for acoustic decoupling. In order to form positive interlocks
in the case of a crash-induced offset of the inclined side rail
portions, the transverse support arrangement has projections that
become engaged in corresponding recesses in stiffening plates
attached to the inclined side rail portions.
Inventors: |
Dolla; Franz (Isenbuttel,
DE) |
Assignee: |
Volkswagen AG (Wolfsburg,
DE)
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Family
ID: |
6389874 |
Appl.
No.: |
07/586,449 |
Filed: |
September 21, 1990 |
Foreign Application Priority Data
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Sep 21, 1989 [DE] |
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3931493 |
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Current U.S.
Class: |
296/204;
296/187.08; 296/35.2 |
Current CPC
Class: |
B60R
19/00 (20130101) |
Current International
Class: |
B60R
19/00 (20060101); B62D 021/00 () |
Field of
Search: |
;296/187,188,189,190,193,194,196,197,203,204,209,35.1,35.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0233505 |
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Jan 1987 |
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EP |
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2145467 |
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Apr 1973 |
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DE |
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Primary Examiner: Focarino; Margaret A.
Assistant Examiner: Pike; Andrew C.
Attorney, Agent or Firm: Brumbaugh, Graves, Donohue &
Raymond
Claims
I claim:
1. An acoustically decoupled underbody for a motor vehicle having a
longitudinal axis comprising a side rail that is spaced apart from
and substantially parallel to the longitudinal axis of the vehicle
and has an inclined portion, the inclined portion of the side rail
having an upper surface; a sill located outwardly of the side rail
relative to the longitudinal axis of the vehicle and oriented
substantially parallel to the side rail; a floor panel having an
inclined portion located above and in spaced-apart relation to the
inclined portion of the side rail; and a transverse support
arrangement that is connected to the sill and to the inclined
portion of the floor panel and overlies the inclined portion of the
side rail and is spaced apart from the inclined portion of the side
rail, the transverse support arrangement having a projection
extending toward the inclined portion of the side rail and the
inclined portion of the side rail having a depression corresponding
to the projection, and the projection normally being spaced apart
from a bottom of the depression.
2. An acoustically decoupled underbody for a vehicle according to
claim 1 and further comprising a stiffening plate fastened to the
upper surface of the inclined portion of the side rail and wherein
the depression is in the stiffening plate.
Description
BACKGROUND OF THE INVENTION
The present invention relates to an acoustically decoupled
underbody and passenger compartment for a motor vehicle and, more
particularly, to an underbody having improved crash resistance as
well as acoustic isolation of the passenger compartment.
German Offenlegungschrift No. 2,145,467 discloses a motor vehicle
having a pair of side rails, a pair of sills displaced outwardly
from the side rails and running parallel to them, and a floor panel
having inclined front regions. Each of the side rails has an
inclined portion toward the front with a provision for spacing them
from the inclined front regions of the floor panel to provide
acoustic decoupling of the passenger compartment.
Except for torsion pads provided between the front ends of the
sills and the side rails, the sills are supported from the side
rails essentially only in the area of their rear end regions. This
support is by way of a transverse connection between the side rails
and the floor panel. It is well known that vibrations coming from
the front of the car may lead to the development of disturbing
noises and rattles in the passenger compartment. Because a space is
maintained between the side rails and the floor panel, direct
transfer of vibration from the front of the vehicle containing the
engine is avoided in order to minimize noise and rattles in the
passenger compartment.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a
new and improved underbody for a motor vehicle which provides both
improved acoustic decoupling and improved crash
characteristics.
An acoustically decoupled underbody for a motor vehicle comprises
on each side of the longitudinal axis of the vehicle a side rail
that is spaced apart from and substantially parallel to the
longitudinal axis of the vehicle and has an inclined portion, the
inclined portion of the side rail having an upper surface. A sill
is located outwardly of the side rail, relative to the longitudinal
axis of the vehicle, the sill being oriented substantially parallel
to the side rail. A floor panel having an inclined portion is
located above and in spaced-apart relation to the inclined portion
of the side rail. A transverse support arrangement, which is
connected to the sill and to the inclined portion of the floor
panel, overlies the inclined portion of the side rail and is spaced
apart from the inclined portion of the side rail. The transverse
support arrangement has a projection extending toward the inclined
portion of the side rail, and the inclined portion of the side rail
has a depression corresponding to the projection. The projection
normally is spaced apart from the depression but is engageable with
the depression upon a crash-induced offset of the inclined portion
of the side rail such as to form a locking connection between the
inclined portion of the side rail and the transverse support
arrangement.
In a preferred embodiment, a stiffening plate is fastened to the
upper surface of the inclined portion of the side rail, and the
depression is in the stiffening plate.
A particular advantage of the invention is that, despite an
improved crash characteristic resulting from engagement of a
displaced side rail with a transverse support surface, no acoustic
connection exists between the side rails and the front of the
passenger compartment during normal operation of the vehicle
because of the absence of contact between the side rails and the
floor panel.
BRIEF DESCRIPTION OF THE DRAWINGS
Further objects and advantages of the invention will be apparent
from a reading of the following description in conjunction with the
accompanying drawings, in which:
FIG. 1 is a fragmentary view in longitudinal section, taken along
the line I--I of FIG. 2, showing a representative side rail and
transverse support arrangement in accordance with the invention on
the left side of the vehicle and is also a mirror image of a side
rail and transverse support arrangement on the right side of the
vehicle
FIG. 2 is a fragmentary top view of the portion of the underbody on
the left side of the vehicle shown in FIG. 1 and is also a mirror
image of a portion of the underbody on the right side of the
vehicle; and
FIG. 3 is an enlarged fragmentary view of a portion of the
structure shown in FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the representative underbody arrangement shown in FIGS. 1 and 2,
only one side rail 1 for one side of the vehicle is shown. It will
be understood that the underbody is symmetrical about the
longitudinal axis 2 of the vehicle so that a second side rail is
present on the other side of a central tunnel 3. Since the other
side rail has the same design as the side rail 1 and FIGS. 1 and 2
are mirror images of the right side of the underbody, illustration
is not necessary.
As illustrated in FIG. 1, the side rail 1 has an inclined portion 4
disposed under an inclined region 5 of a floor panel 6 of a vehicle
passenger compartment 10. The floor panel inclined region 5 is
attached to a closed transverse support arrangement 8 having an
inclined transverse profile 7 adjacent to the inclined side rail
portion 4. The transverse support arrangement 8 extends between the
aforementioned central tunnel 3 and a sill 9 shown in FIG. 2. The
sill 9 and the corresponding sill on the opposite side of the
vehicle (not shown) runs parallel to the adjacent side rail 1 and
is displaced toward the outside of the vehicle. Moreover, the front
of the sill 9 ends in the region of the transverse support
arrangement 8 described above.
In order to prevent the transfer of sound from the side rails 1,
which also serve to support the motor of the vehicle, to the
passenger compartment 10 and to the floor panel, a space 11 is
maintained between the upper surface 4' of the inclined side rail
portion 4, and the adjacent facing surface 7' of the transverse
profile 7 of the transverse support arrangement 8. The two side
rails 1 are connected at their rear ends by way of, for example,
additional transverse supports for the sills (not shown) and, if
desired, by further transverse connections (not shown) behind the
inclined regions 5 of the floor panel 6.
It will be understood that the space 11 between the side rails 1
and the transverse supports 8 reduces the structural integrity of
the underbody in the case of a frontal impact which forces the side
rails 1 into the sills 9 and the floor panel 6, causing an
undesired buckling of the passenger compartment. In order to
prevent this loss of structural integrity under frontal impact in
accordance with the invention, there is provided not only an
attachment of the floor panel at the inclined base region 5 to the
transverse support arrangement 8, but, in addition, the adjacent
facing surfaces 4' and 7' defining the space between those members
are arranged to form locking connections in the event of
crash-induced offsets in the inclined side rail portion 4. For this
purpose, the inclined side rail portion 4 is provided with a
stiffening plate 12 which has depressions or recesses 14 to receive
corresponding projections 13 on the transverse support arrangement
8. The projections 13, for example, may be normally disposed within
the depressions or recesses in the side rail portion 4 but in that
case care must be exercised to see that there is no contact between
the projection and the stiffening plate 12 in normal operation of
the vehicle.
Alternatively, the projections and recesses may be arranged so that
the projections enter the recesses only when a crash-induced offset
of the side rail region 4 has occurred. In either case, application
of forces from the side rail 1 to the transverse support
arrangement 8 and from the latter to the sill 9 and the tunnel 3 in
the event of a crash is ensured by the stiffening plate 12.
Positive interlocking of the projections and corresponding
depressions may, of course, be produced in some other way, for
example, by suitable design of the facing surfaces of the inclined
side rail portions 4 and of the transverse support arrangement 8 so
that these surfaces can become engaged with each other in the event
of a collision.
Thus, the invention provides an underbody which, while assuring
favorable acoustic behavior, is effective to transfer force from
the side rails into the other regions of the underbody in the event
of a crash.
Although the invention has been described herein with reference to
specific embodiments, many modifications and variations therein
will readily occur to those skilled in the art. Accordingly, all
such variations are included within the scope of the invention.
* * * * *